The following description of the prior art and of embodiments in Applicant's previously-filed applications, PCT/AU01/01175 and U.S. patent application Ser. No. 10/275,530, are not intended to be, nor should it be interpreted as, an indication of the common general knowledge pertaining to the invention.
Traditionally, caster wheels have been used to provide wheel support for a wide range of items for which mobility is desirable. The caster wheel has a single wheel rotatable about a general horizontal axis which in turn is mounted to a substantially vertical axis thereby enabling a wheel to travel in any direction from which it is pulled. Caster wheels are generally made of multiple components made of different materials and can require a costly and involved manufacturing process. Moreover, the caster wheel is generally mounted on an object to be moved by a vertical axle making attachment of the wheel to the object sometimes difficult to achieve as access to the underside may be limited and/or awkward.
More recently, another type of wheel capable of multiple directional travel has been considered and includes a central hub rotatable about a main axis and a number of independently mounted rotatable rollers located about the rim of the hub. An improvement on such types of wheel has been described in International Patent Application No. PCT/AU01/01175 by the present applicant and published as WO02/24471, and in U.S. patent application Ser. No. 10/275,530, which is herein incorporated by reference. The multiple directional wheel as described in that specification was constructed by molding or casting a pair of polyaxled rings comprising a plurality of evenly spaced axles about the circumference of each ring. The method then involved the assembly of a roller about each corresponding evenly spaced axle of the multi sided ring. The finished polyaxled rings were then pressed into a wheel frame and the final product was sealed with the corner portions of the polyaxled ring being fixed to supports of the wheel frame. This manufacturing process is complex as a polyaxled ring is required to be molded separately from that of the remainder of the wheel.
Moreover, the applicant's previously described multiple directional wheel requires the polyaxled wheels to be used in pairs, their adjacent rollers offset relative to one another to ensure good ground contact.
Accordingly, a multiple directional wheel which is relatively inexpensive and simple to manufacture compared to existing wheels and/or a useful manufacturing method alternative to existing wheels is desired.